In some industries such as nuclear and aerospace, we have a requirement for 'fitness-for-duty'. If a worker shows up intoxicated (impaired), he/she can be fired (or in some cases just suspended pending treatment).
I used to work construction. One of the workers used to show up in the morning after drinking (he claimed a 6-pack of beer). He was not very useful on the iron (safety issue), so he did ground work. Well, he managed to rewire some of our drills and screw motors. However, he switched the ground wire and hot(live electrical) wires. One of my coworkers working on the edge of a metal roof got electrocuted (he could have easily fallen over the edge - 10 m to the ground). I was working on an aluminum ladder about 9 meters above ground, sweating profusely, when I got electrocuted. My legs almost collapsed. Fortunately I fell against the ladder, dropped the drill and caught myself rather than falling backwards.
Our drunk colleague was dismissed. His 'freedom of choice' (and total lack of responsibility) almost killed my friend and me. Yeah, I suppose we could have made allowances for him being drunk and unable to work. But why?
What is the policy for someone who wants to drink for a long period of time?
I certainly don't drink as much as I did during my first years of college. Even then though, I would confine my social drinking to the end of the week or weekend. During the week, I would drink a few beers perhaps, but usually with food. Now I will occassionally drink one or two beers after work (or on weekends), but not evey day, and it is often with dinner.